linux-kernel - Re: [PATCH] ALSA: trident: Fix a memory leak in snd_trident

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Date:   Sat, 11 Jul 2020 11:04:12 +0200
From:   Takashi Iwai <tiwai@...e.de>
To:     Navid Emamdoost <navid.emamdoost@...il.com>
Cc:     Jaroslav Kysela <perex@...ex.cz>, Takashi Iwai <tiwai@...e.com>,
        alsa-devel@...a-project.org, linux-kernel@...r.kernel.org,
        emamd001@....edu, kjlu@....edu, smccaman@....edu
Subject: Re: [PATCH] ALSA: trident: Fix a memory leak in snd_trident_create

On Sat, 11 Jul 2020 09:08:30 +0200,
Navid Emamdoost wrote:
> 
> In the implementation of snd_trident_create(), the allocated trident is
> leaked if snd_trident_mixer() fails. Release via snd_trident_free().

No, this patch would result in double-free.

The manual release of trident object isn't needed once after it gets
added via snd_device_new().  Then it'll be automatically released at
the error path (via snd_trident_dev_free()).


thanks,

Takashi

> 
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Signed-off-by: Navid Emamdoost <navid.emamdoost@...il.com>
> ---
>  sound/pci/trident/trident_main.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/sound/pci/trident/trident_main.c b/sound/pci/trident/trident_main.c
> index 6e50376163a2..e98c692f6aa9 100644
> --- a/sound/pci/trident/trident_main.c
> +++ b/sound/pci/trident/trident_main.c
> @@ -3582,8 +3582,11 @@ int snd_trident_create(struct snd_card *card,
>  		return err;
>  	}
>  
> -	if ((err = snd_trident_mixer(trident, pcm_spdif_device)) < 0)
> +	err = snd_trident_mixer(trident, pcm_spdif_device);
> +	if (err < 0) {
> +		snd_trident_free(trident);
>  		return err;
> +	}
>  	
>  	/* initialise synth voices */
>  	for (i = 0; i < 64; i++) {
> -- 
> 2.17.1
>